Wheel alignment gauge



Oct 1946- J. L. CREAGMILE WHEEL ALIGNMENT GAUGE Filed Feb. 15, 1943 s Sheets-Sheet 1 w i WED-HUME kw .k.

INVENTOR JOHN L. CREFIGMILE ATTORNEY Oct; 29, 1946, .1. 1... CREAGMILE WHEEL ALIGNMENT GAUGE Filed Feb. 15, 1943- Sheets-Sheet '2 INVENTOR JOHN L. CREflG/WLE ATTORNEY 1 J. L. CREAGMILE I WHEEL ALIGNMENT GAUGE Filed Feb. 15, 1943 3 Sheets-Sheet 5 INVENTOR mi L Patented Oct. 29, 1946 .,epi eiieer niieez'1 a em The invention relatesto a means for gauging various aligmnent relations of dirigible wheels of vehicles. e p e ,c The'general object of the'invention' is to 'provide an improved and particularlysimple device for gauging such features 'asfthe camber, caster, toe-in, and turning, radius ofthe dirigiblewheels' of vehicles while the wheels are mounted on the vehicles. j' a A- more specificlobject is to provide a" particularly simple and efiectivedevice for utilizing abeam of light inefiecting the "aforesaidgauging operations, the device comprising an optical A further object is to provide'a. simple and ef fecti ve 'means for'rnounting a reflectorof the apparatus upon wheels beingj gauged for, their alignmentrelations; H V I "The invention possesses other objects andfea tures'ofadvantage, some of which, with'the foregoin will be set forth or be apparent in the following description of "a typical embodiment 'of the invention; and in the accompanying drawings; in which, '7 I c t Figure 1 is a fragmentary plan view illustrating .themethod of using thepresent apparatus forgauging' the toe-in and camber ofra'pair or dirigible-wheels of 'a motorvehicle. I V

"Figure-2 is afragmentary plan view showing the apparatus in use for gauging the caster and turnin rad us relations of the Wheels." p Figure '3 is a front elevation of the assembly of the Figures land '2; the wheels being set, in straight-ahead position with respect to" the vehicle. 7 e m j Figure 4 i s-an enlargedplan sectionpf t'he left-side wheel and associated gaugingfappa; ratus shown-inFigure 1; the sectionbeing taken generally a t-the central diam etrical plane ofthe Figure "5 is a front sectional elevation of the combination of Figure! taken generallyatfla fixed beam line providedby the apparatus; v

Figure 6 isa full-face elevation of'afga'uging screen comprising-part of the apparatus. 7 Figure 7 is an outsideelevtttion of a bracket for mounting reflectors of-the'apparatus on a Figure 8 is a sectional viewtakenat;-the'line 88*in-Figure '7. 5 v -Figure 9 is a 'fragmentary'plan' view at the scale-of Figure-4, and {shows theifunc'tioning of the gauging apparatus for a predetermined rightturn wheel position. t f' Q s i y i e wt pa augi apparatus i TESRATENT v .I2,410,3 r;

1" wh n, g ipes e J nn L.'-Creagmile, Oakland; cent; n

I l V V 5, 1543, Serial Nil-Ifi75e9f15 j i (area-74f; a

fijiii ported for their fsteeringTswinging about ifixea.

points," suitablellig'htc sources I3 for directing light. beams horizontally toward the wheels in a common j line which lies in a vertical I plane through or immediately adjacent the support points of the wheels and complementary reflector.

' sets remov'ably mounted upon" the different whee s in definite relations thereto and havingrefie'ctors thereof arranged to be selectively interposedin the'bea'm lines in accordance 'with'the dis-Y positions of the wheels to reflect the intercepted beams upon scales provided on the opposed faces of the corresponding screen's l0;

' 'Each'present'scr'een member. 10' mountsa light source'l3, and has its graduated face perpendicu' larto the "light beam from the light source nd provided with scales I4 and I5 at difierenticalibrated zones 'ofjsaid face'., ,The scale I4 is pro--' vided adjacent and. about the unitary "beam source I3 for itsjusejini toe-in and c'ainber measurements, and the scale, I5 is .positioned'forwardlyrof the "scalejlA for its' usein'icastor'an'd turning ra'dius" determinations. V I 'he scale [14 has an;interrnfediate; vertical zero line '16. interseoting thebeam 1ine,'thef scale l5has an intermediate'verticalflzero line IL, and thescalesll l andljhavexja COmmOnij horizontal zero line I8 intersecting the 'be'amiline; The scales l4 and 15 may be calibrated for angle'degreesrwith respect to the various zerolines thereof, or the lines of the calibrations may be arbitrarily ,nur'nbered for reference. In eithe'rl case it will be understood that the actual determinations made for a vehicle having its wheel alignment under investigation with the presentapparatus are c'om-i pared-with the values intendedfor the Wheels by the vehicle'manufacturer; I 'The beam 'sources'ls comprise any suitable uni; tary devices for providing the 'beams and may; for instancej include electri'c lamps enclosed in suitable housin s from whichthebeamsiareiprojected as: pencils or lightfl'of uniform or slightly contracting cross-section, as by) the i actioniof lense /or' et 1 ntheih sin s; the. use or an electric lamp as av sourcefof light "for a present beam is assumed .in the present. appa -fl ratus; The detailsj'of thej'bearnisourcesjl3 are. not shown; as they 'are aside from the scope of the present features ofinvention; 1 j I Bracketassemblies" I 9 "a're provided for mountingr the sets of reflectors on theidifierent wheels 6 [I and I2 in predetermined relation thereto, each reflector set comprising a rear reflector 2| and an intermediate reflector 22 and a front reflector 23. in mutually fixed unitary relation to the supporting bracket. Each mounted reflector 22 has its reflecting face fixed in parallel relation to the plane of the wheel which mounts it whereby, when the wheel is in straight-ahead position, the horizontally projected light beam from the opposed light source'l3 will be reflected from the reflector upon the screen 18 at a point in the vertical zero line I6 of the scale I4. be understood that a straight-ahead setting of the wheel is readily and accurately effected merely by so disposing the wheel that the bean reflected from the reflector 22 strikes a'point of the vertical zero line N3 of the scale [-4. Because of camber, the point at which a light beam reflected from a reflector 22 strikes the 6p po s; screen I! h llcl e be ow he hor o ta Zero line I? f the scales Hi and L by'an amount Which repre ts: the angle or. camber for. the wheel-mounting the reflector," said: angle being e s o e o t e wh l m un n p n he wheel is in a 's'traightahead position, as is assumed for the wheel lZin Figures 1 and 3. For measuring camber, it is merely necessary'to so fa Wheel whi h is b gau ed f a e that th e beam reflected from the reflector 22 me ted Qfl' st ke a point ini V r zero line lfiof the scale 14, with the location of said; point with respect to the horizontal'z'ero me 18 of the scale I 4 comprising a direct camber ete mination; a. n eaWR e 9f. h camber angle for thewheel l2 is'indicated in Figure 3.

Recalling that th 'twfo. dirigible wheels of a motor vehicle for hig way travel are connected forsin ult 'neeus' sw nging in steering the vehitie; the s ettingfof one whe l .in true straightahead position should, becauseof toe-in, cause .a herilzontallyangular reflection of'the beam from the reflector 2;? Qt the other wheel to strike the opposed screen Ill at a point of its scale 14 which is: forward ofth e vertical zero line [6 of the scale, it being understood that the turnan'gle of the second wheel thus measured horizontally actu ally comprises the. sum of the. toei'n angles for the. wheelsiand'rnaybe considered as twice the to'e in angle for either wheel for. gauging rposes; A measurement of toe-in is indicated in Figured; with'the e112, in straight-ahead position and the total t e in reading for both wheels arranged t b 'tgken at the scale M opposite the he r l l It will now be, noted that thej'refle'ctors 21' and 2 5m provided both for measuring simultaneous differences in the angles of turning of thewlieels from straight-ahead positions thereof and for measuring changes in the angularity of the turried wheels with'respect to the verticallthefineas ure ments being respectively made withiererieme to the vertical zero line H of the scale asking to the hprizontalzero line IQ of the scales l4 and 15. With particular reference to the scales Hi, the vertical z ero 'lines 11 thereof are arbitrarily'and correspondingly. positioned on the screen"!!! to represent a axes and predetermined turn angle t for the wheels, said anglei t being twenty flve degrees in the present instance. ljor reasons which arehereinga'fter brought out, the planes of the reflecting faces of the"reflectors 21 and 2 new ihe a h ee in he o the associated reflector. in lines which are mutu: ally, parallel andlare disposed a vertical plane fii lu s the e rin oi t of t e Whe l du ng reading on a scale [5i Figure 2 shows an angle i It Will thllsj 4 left-turn setting for the left wheel l2, while Figure 9 shows an angle t right-turn setting for said wheel.

For caster determinations with the present apparatus, one wheel is set in either a left-turn or right-turn position with the light beam reflected from a reflector 2| or 23 striking the opposed screen ill to provide a reading at a point of the vertical'zero-line I! of its scale 15 The latter scale reading provides a caster determination when referred to the horizontal zero line l8 of the scale in comparison with the camber reading from the reflector 22 with respect to the same zero" line, provided the line of intersection of the reflecting faces of the reflectors used is in a. vertical plane including the point of support of the wheel carrying the reflectors. The two readings thus obtained with respect to the zero line 18 are, for instance, those obtained from the reflectors 22 sad 2% when t le Wh e '2, is es e ti r 3 q l q nv he d igent nes q' Sh wn q lit n Figures 1 and 2, it being understood that caster e e mi i re made nd idual for i ed fe'r'ent wheels v 1 Fe rhinwa ius determina ions one wh l. is, Set in imp ess o a e a d s de ermin tion nd h p int a w i h light am e ec e from the'r'eflector 2! or 23 ofthe second wheel strikes the opposed scale I 5 supplies a turningradius determination when referred to the vertical zero line H, of the scale. lnthis manner, the dif: ference in the angles of turning of the two wheels is ascertained as a turning-radius determination. 1 Particularly ows i F ur 2 t hee s and I; are both disposed in left turn positions, and with the Wheel .12 assumed to. be set for the striking of the beam reflected from the. forward reflector 23 on he opposed Cale. l5 at a point in the vertical zero line I? of said scale; under these circumstances the. left-turn angle "for the Wh l l ij u bhan the angle h ou which the wheel 12 has been turned from straight; ahead, it being recalled that the proper alignment I relations of thedirigible wheels of a landvehicle requirethat the axes" of rotation of both wheels intersect the same vertical line in a vertical plane through the axial line of the non-dirigible wheels when the dirigible wheels are set for a turning lithe. vehicle from a straight-ahead line.

The support brackets l9 are arranged for removable mounting directly on a usual wheel rim 2; which mountsa pneumatic tire 25 on a wheel hub structure: 26. In the present wheel structure, the rim 24 is fixedly'moun'ted on a cylindrical pie ripheral portion of a disc. 21 which is bolted to the outer. endv of the hub structure. 'Ifh'e rim 24 is provided with usual circumferential right-angle inside corners orgrooxjes' 28 at its opposite sides,

said corners each being defined by flat radial rim portions 29 and cylindrical rim portions 3l at the outer. edges of the portions 2 9, and the means for mounting the sets, ofreflectors on the wheels utilizes said corners atthe outer wheel faces.

Each present bracket lilbomprises a base plate m b r n ise h ta le, rms ar an to have their extremitiescooperatively-engage the rim corner 28 at the outer wheel side for mount-.- ing. the plate on the rim. As shown, the plate 32 is generally rectangular, and has one piece arms 33; fixed at adjacent corners thereof and having th x rem i s a r n ed r fil esn a ment i he i corner at qne r iie es o the plate 32 from the arms 33, the plate 32 slidably m tels aims henc their: reewheelin al arranged for engagement in a rim corner 28, said ager sso ar'msbeing shown as mounted in guide sockets 35 ifriomwhichtheiruextension is constantly u'rgedb'y .the'a'ction of springs'36. engaged betweenithe opposed inner ends of the socketsv and of theslidable arms; The innerends of set-screws?! mounted 1115a side of each socket 35 engage slotsu38prolvidedfin the opposed sides ofthe arms34, said slots/terminating. short of the innerarm ends Iwhereby theinn'er slot ends maycoact witnthe 'setscrews 73? tolimit the extension of the arms :from the socketsunder the infiuence of the springs -36;" The arrangementis such that :a plate 32 may he firmly andaccurately mounted on a wheel rim 524m exact parallel relation tothe plane of the rim iand wheel by engagingwthe appropriately formed extremities of the arms 33 and ii i inthe corner :28'in simultaneous. engagement with the-corner sides 29 and 31.. The arrangement alsovpriovides for the mounting of'aplate 32 on rims ofdifierent sizesinvtheusual range ofisize for such rims, it :bein'g'noted that the rim-engaging portions of the various arms 33 and 84 are offset from the -planebf the plate 32 110 dispo'sethe mounted plate 'c'lear of the wheel portion at the side of .a wheel -whichis to mountit. J r l Ihe reflectors 2! and 22 and 23 of a set are mounted on a block 38 which is fixed by means of a bolt ll against the outer side'of the plate 32 to dispose the reflector22 in parallel relation to the wheel plane, the various present reflectors being rectangular. -In-the present structure, the reflectors 2| and 23 are in such angular relation tothe reflector 22 that the forward screen scales 15 may be'used for gauging readings with either left-turn or right-turn wheel settings. While the screens might extend rearwardly of the beam sources I3 to provide the-scales i5, or provide scales l5 both forwardly and rearwardly for the projection thereupon'of beams'refiected from themirrors 2| and 23, the disclosed position of the scales I5 for use in measuring turn positions and caster efiects is generallythe most practical as best providing for the simultaneous visibility of both scales of both screens to an operator positioned infront of the vehicle. a V P It will now be noted that the gauging use of the turn-measuring reflectors 2| and 23 requires a particular positioning ofthese reflectors because of the fact that straight-ahead andturn readings obtained from different reflectors are to becomjpared as a gauging-means. If the-wheels H and l2-had neither camber'nor caster, the disposal of reflectors 2i and 23 to vertically position the parallel intersectionlines of the planes of their reflection faces with that of the reflector face of 'the associated reflector 22 would provide readings solely along the scale zero line [8 of the opposed screen as true angularity measures with respect to straight-ahead wheel positions. Actually, be- :cause of camber and caster, said intersectionlines ofithe. reflection faces of therefiectors, while parallel to the wheel plane, must be out of the vertical in vertical planes including the bearing -:point of the wheel, said bearing point lying substantially in the axisof the king pin 42 about which the. wheel is swung in turning. Accord-' 'ingly, means. are provided for setting therexfiector's as described and required, said means in ithenp'resent case comprising a level bubble .43

mountedion eachzblock 39 and havingits longitudinal line perpendicular tothe aforesaid inter- :se'ctionslinesof the flat reflectorifaces ofthe threerefieotors ofrthe set whereby'the rotation -01, the carrying wheelptov level thetbubhlejabout sthelwheelzaxis, which;c.omprises;thellev lin lin c 6 of. the bubble, will position. the. reflectors rasire- 'quired for a proper reading; arotary resetting, of the reflectors by. usegof :the levelling means will usually be r'nec'es'sa'ry, after each :jchange, inthe turn angle of the wheelbecause of, the ,action of the 'camberand caster onthe'r'angularity f-the iwheelwithirespect to the Vertical; 3 :j Noting that the effective axis oflswingingrof the whel" is approxirnately'a vertical :axis through the bearing-i pointof the tire v25; the. reflectors 12 l and 22 and 23 are-preferablyrarrangedisatcequal distances from" said axis for. an; average-sized wheelrim whereby their effective distances from the opposed screen 10. maybe substantially the same .as the wheel is turnedybecause' of the pitcenterswinging of the "reflectors as the wheelr-ls turned, the reflectors are actually spaced in Jan -arci1ate 1ine. Also, when the disclosed "brackets 19 are mounted on "rimsof;difieren-tisizepthey thereby dispose a reflector assembly at different heights from the plane of support ofthegwh'eels. Since'the beam line: is at'aafixed level, :the' reflectors must be of suflicientiheightwhen in position for'use to provide for theirdescribed strike ing' by and reflections .of. the beams for avusual range of rim'and tire sizes as affecting the. heights of disposalofthe reflector assemblies. "1'. 2; 1;?

; While av vehicle may have its wheel alignment relations gauged with the present apparatus while supported independently of its dirigible. wheels, more dependable results are 'obtainabl'eiif the gauging operations are effected .while the vehicle is supported upon all of its wheels'with theplane of support horizontal. Accordingly, I prieferito support the dirigiblewheels on individualeturntable assemblies. Because the bearing point of -a turning dirigible wheel shifts slightlywith respect to the fixed vehicle body, frictionalefie'cts on-the'tire at itsbearing point areipreferably eliminated by permitting'a lateral shifting of the tire-engaging turntable member with the point. As brought out inFlgure 5, eachlturntable assembly comprises a disc '44 having :a slightly cupped upper face rotatably jmountedin a circular depression 45 of somewhatgreaterdiame-ter 'than-the discprovided in the top 4670f a hollow base member 41 set'into a'support'fioor F to dispose the upper disc face in flush relation with .the'upper floor face, r a v;

Thepresent base top 46 is provided witha circular central opening 8 to freely receive a stem 49 depending integrally fromthe disc, the size of the opening determininga permitted lateral shiftingofthe disc from its centeredposition in the base're'c'ess. A flat anti-friction bearing 'ring 5| is operatively disposed between'the disc 44 and the bottom of the depression t5 for suppor ting the disc upon thebase for its lateral "shifting, and tension springs- EZ-radiating. from the stem 49 to points of attachmentwi-th' the side walls of the base cavity constantlyand-yildingly urge a rotative and lateral centering ofthe disc in'the depression 45, it being understoodthat the mutualspacingof the discs 44 designedto simultaneously support the two 'dirigible wheels of a motor vehicle'is the same 'asthesp'acin'g of the bearing points of the wheels when the "vehicle is travelling straight "ahead.- It will now be noted that wheel rims 24 of different diameters frequently have different widths "at the rim grooves 28, such widths increasing generally withithe rim diameters, whereby the spacing or an operative reflector of a mounted" refleotor a'ssernbly from. .theffopposje'd Scre'n'j l 0" will vary and so change "thesigififican ej' of, he

nations ofthescales I 4' and L5 unlessthe; re-

fiector and screen are relativelyadjustable for providing the same spacing of the reflectors and screens for all rim widths. While means; might be provided for axially adjusting the mirror-carry-ing block 39 on the bracket I9, I prefer to adjust the screens as required for maintainin the latter at the distance d. from the reflectors for which the graduations of the scales IA and Ihave been provided, it being recalled that the three reflectors of a set are used while arranged in a common horizontal are such that corresponding horizontal lines of the reflectors. are equally spacedfrom the axis of turning of a. wheel having an average-sized rim. With reference to present wheel rim sizes, it, is. noted that the variation in widths is no more than four inches whereby the required range. ofrelative adjust ment of a reflector set with respect to the opposed screen for a fixed spacing of-the reflectors and a screen is no more than twoinches and may be ignored in the middle range of rim Widths.

For providing the aforesaid positioning adjustment of the screens It, as may be needed or desired, each of said screens is mounted on a pair of blocks 54 which are in turn slidably mounted in guideways extending in lines parallel to the beams from the beam sources l3 and provided in base members 55 fixedly embedded in the floor F. The tops of the blocks 54 and of the base members 55 which receive them are flush, and registering upper faces of the, blocks and members are conveniently calibrated in terms of rim sizes for facilitatin the setting of the screens at the desired distance d. from the corresponding reflectors.

Understanding that welleknown and appropriate corrections are made withrespect towheels which are found to be misaligned by the use of the present gaugin apparatus, it will be noted that the necessary correction adjustments or operations may be performed on the, vehicle structure without, dismounting; the reflector assemblies or disturbing the remaining parts of the present gauging apparatus which are'free, of the wheels and vehicle. In this manner, the eifects of correction adjustments or, operations may be observed as they are madewhereby. to save time and avoid over-corrections.

From the foregoing description, talgenin connection withthe accompanying drawin fi fihe, adr vantages of the construction and use-of thepresent alignment-gauging device will be readily understood by those skilled in the art to which the-invention appertains. While I have described the features and use of; an arrangement, which I now consider to be a preferred embodiment of my invention, I desire to have it understood that the showing is primarily illustrative, and that such changes may be made, whendesired, as fall'within the scope of the following claims.

,Iclaim:

1'. In apparatus for gauging an alignment relation of a dirigible wheel disposed for its swinging in place about an upright axis, an optical indicating means comprising a fixed sourc or light emitting a lig t beam directed horizontally in a line toward said axis; of swinging for the wheel, a reflector mountedon thewheel for its disposal to intercept said lightbeam for the reflection thereof and having its reflecting, face parallel to, the plane of the wheel, and. a fixed. scale disposed, to intercept the reflected beam at, a point, in a vertical zero line of the scale intersecting the beam line when a horizontalline of said" reflecting face the beam line.

2. In apparatus for gauging an alignment relation of a. dirigible vehicle wheel disposed for its swingingin place about an upright axis and from a straight-ahead position of the wheel with respect to. the vehicle, an optical indicatin means comprising a fixed source of light emitting a light beam directed horizontally toward the wheel in a line perpendicular to a horizontal line in the wheel plane when the wheel is in straight-ahead position, a flat reflector mounted on the Wheel for its disposal to intercept said light beam for the reflection of the beam when the wheel is in a substantially straight-ahead position thereof and having its. reflecting face parallel to the plane of the wheel, and afixed scale disposed to intercept the, reflected beam at a point in a vertical line through the. beam line from the source when the wheel is. in straight-ahead position, said scale having. vertical and horizontal calibrations re,- ferred to said beam line from the source for the gauging of turn and/0r. camber angles of the wheel.

3. In apparatus for gauging an alignment relation'of a dirigible Vehicle wheel disposed for its swinging in place about an upright axis and with respect to a straight-ahead position of the. Wheel with respect to the vehicle, an optical indicating means comprising a fixed source of light emitting a light beam directed horizontally toward the wheel in a line perpendicular to a horizontal line in the wheel plane when the wheel is. in straightahead position, a flat reflector fixedly mounted on the wheel for its disposal to intercept said light beam for the reflection of the beam when the wheel is in a substantially straight-ahead position thereof and having its reflecting face paralle to the plane of the wheel, asecond flat reflector-fix.- edly; mounted on the wheel for its, disposal upon an appreciable turning of the wheel from its straight-ahead position to intercept said. light beam for the reflection thereof and having the plane of its reflecting face angularly related to the planev of the reflecting face of the first reflector and intersecting the latter plane in a line parallel to the plane of the wheel andarranged'for its disposal during the gauging; use of; the reflectors in a vertical plane including the bearing point, of the. Wheel, and a fixedscale; disposed to intercept the reflected beam fromthe di ferent respective. reflectors when the Wheel is in straight.- ahead and turn positions thereof, said. scale having vertical and horizontal calibrations referred to said beam line from the lightv source for the gauging of turn and camber-angles, of the wheel.

4. In apparatus for gauging an alignment, relation of a dirigible vehicle Wheel; disposed for its swinging in place about an, upright axis and for its rotative turning in place, an optical indicat: ing means comprising aflxed source of light, dirrecting a light beam horizontally toward the wheel in a line perpendicular, to a horizontal line in the wheel plane when the wheelie in straightahead position, a support member removably fixed on the wheel at its side towardv the. light source, a flat reflector fixedly carried by thesupport member in position thereon tointercept said light beam when the wheel is in asubstantially straighteahead position thereof. and: having the plane of'its reflecting face parallel to the plane of the wheel, a second flat reflector fixedly-mounted on the support member inposition thereon; to intercept said light beam upon an: appreciable angular swinging of the-wheel from itsstraight ahead position and having the plane of its reflecting faceangularly related to the plane of the vertical plane including the bearing point of the wheel, and a fixed scale disposed to intersect the reflected beam from the different respective reflectors when the wheel is in straight-ahead and 5 turn positions thereof.

JOHN L. CREAGMILE. 

